ausblenden:
Schlagwörter:
STAR-FORMING REGIONS; CO ROVIBRATIONAL EMISSION; EARLY PLANET FORMATION;
WEBB-SPACE-TELESCOPE; LOW-MASS PROTOSTAR; KEPLERIAN DISK; WATER-VAPOR;
MIDINFRARED INSTRUMENT; ALMA OBSERVATIONS; SPITZER SURVEYAstronomy & Astrophysics;
Zusammenfassung:
We present James Webb Space Telescope (JWST) Mid-InfraRed Instrument (MIRI) observations of warm CO and H2O gas in emission toward the low-mass protostar IRAS 15398-3359, observed as part of the CORINOS program. The CO is detected via the rovibrational fundamental band and hot band near 5 mu m, whereas the H2O is detected in the rovibrational bending mode at 6-8 mu m. Rotational analysis indicates that the CO originates in a hot reservoir with an excitation temperature of 1598 +/- 118 K, while the water is much cooler at 204 +/- 7 K. Neither the CO nor the H2O line images are significantly spatially extended, constraining the emission to within similar to 40 au of the protostar. The compactness and high temperature of the CO are consistent with an origin in the embedded protostellar disk, or in a compact disk wind. In contrast, the water must arise from a cooler region and requires a larger emitting area (compared to the CO) to produce the observed fluxes. The water may arise from a more extended part of the disk, or from the inner portion of the outflow cavity. Thus, the origin of the molecular emission observed with JWST remains ambiguous. Better constraints on the overall extinction, comparison with realistic disk models, and future kinematically resolved observations may all help to pinpoint the true emitting reservoirs.
